The present invention relates to the field of mining equipment and particularly to the field of highwall mining equipment. The invention is an apparatus designed to facilitate the retrieval of mining equipment, particularly highwall mining equipment, which has become trapped or otherwise lodged within a mine.
Since ancient times, humans have dug mines into the ground and into the sides of mountains in search of ore, minerals, metals, fuel, and other resources which are scarce on the surface. Likewise, since ancient times, among the dangers concurrent with the field of mining is the risk of the collapse of the mine. As miners dig into the ground or mountain, they extract rock and soil leaving behind a void. As the material surrounding the void shifts and settles, there is an inherent danger that the mine will collapse filling the void with debris. Since ancient times through to the present, miners have been trapped, injured, and killed in such collapses. In order to avoid such dangers to miners who enter the voids created by mining, it is desirable to conduct mining operations by way of mechanical mining controlled remotely from the surface.
One such mining operation where mining is accomplished via mechanical mining equipment controlled from outside the mining void is highwall mining. Highwall mining is especially useful in the mining of coal. In highwall mining, various imaging and sensing systems detect and map a seam of coal located within the ground, a mountain, or a hill. A “wall” is prepared on the mountainside or hillside or on a wall of a prepared trench that is substantially vertical to the horizontal and located near a beginning point of the coal seam. Typically, a large mining head cuts into and penetrates the mountain and coal seam. A pushbeam transfer mechanism pushes the mining head into the coal seam. The pushbeam is hydraulically pushed and driven by a large platform based piece of equipment. The pushbeam is typically made of segments which are added one to another as the mining head penetrates and pushes deeper into the mountain. The pushbeams may slide along the floor of the mine or they may have wheels attached. Each segment of the pushbeam typically includes internal augers or other transfer means which ferry the pieces of mined coal internally through pushbeam and out of the mine. Typically, the mining head is designed to move up and down within the coal seam to capture the entirety of the coal seam. Sensors positioned near the mining head help a miner operator determine that the mining head is within the coal seam and not within rock or other material. For instance, measures of specific power draw may indicate that the head is in rock, coal, or looser material. Cameras or other sensors may also be used.
Using such a highwall mining system, the mining head and multiple pushbeams may penetrate more than one thousand feet into a coal seam without the need for a human operator to enter the mine. However, though the use of highwall mining systems may minimize the danger to human life, the use of highwall mining systems does not necessarily minimize the chance of a collapse occurring or the financial risk of such a collapse. Unfortunately it is not uncommon for mines to collapse while highwall mining equipment is positioned within a mine. Further, as highwall mining equipment is expensive, potentially costing several millions of dollars, it is desirable to be able to extract highwall mining equipment from collapsed mines. It is also desirable that the time to extract any mining equipment from a collapsed mine be minimized as downtime for such expensive equipment can quickly increase the detrimental financial impact of a mine collapse.
Under the current state of the art, when a collapse occurs in a highwall mining operation while the highwall mining equipment is located within the mine, there are limited, time consuming, and costly options for proceeding. First, the operators can choose to leave the equipment in the mine and abandon the equipment. Such a course can be wasteful and extremely costly. Second, the operators can attempt to minutely “rock” the pushbeams back and forth using hydraulics of the pusher. That is, they can attempt to push forward a little and then retract a little with hopes of dislodging the mining head and pushbeams. However, as the pushbeams and hydraulics that push them are geared primarily to push and drive into the mountain and not to extract, this process is often unsuccessful and, in any event, time consuming as the hundreds or even a thousand or more feet of pushbeams are moved back and forth by the inch. A third approach is to create another mine directly above the collapsed mine with hopes of opening up the collapse and dislodging the mining equipment. However, as mining is highly regulated by the government and approval must be obtained for each mine, such an approach can be time consuming pending approval by the government. And, in any event, a second collapse may well ensue thus resulting in the loss of a second set of pushbeams and mining heads. A final method is likewise time consuming as it requires approval of the government: sending a human into the mine to inspect the collapse. This method is also disfavored as it places human life in jeopardy and undermines one of the primary benefits of highwall mining, namely that humans need not enter the mine. It is also costly as specialized bracing must be built into the mine for safety purposes before humans may enter.
Thus, there is a need in the art for a mining equipment extraction method and apparatus that preserves the safety of human life and that is time and cost efficient.
Further, under current highwall mining operations, if extraction is attempted via the procedures outlined above, the external equipment must be secured to the ground. Securing is required as there is a tendency for the external equipment to pull towards the highwall once a collapse has occurred and extraction is attempted. However, there are tight governmental regulations which require the external equipment to remain a specified distance, such as twenty feet, from the entrance of the mine. If the equipment moves too close to the mine entrance, human life may be placed in danger and government regulations may be violated. Currently, the practice in the art is to drive large metal rods into the ground to secure equipment. However, this practice can be difficult and costly considering the ground is often solid rock. Further, the driving of the rods may trigger additional collapses. Thus, there is a need in the art for a method of securing the external equipment that keeps the external equipment in place and away from the face of the highwall during extraction of internal mining equipment such as the mining head and pushbeams.